1. Field of the Invention
The present invention is directed to a method and apparatus for delivering, manipulating and repositioning a guidewire to and beyond an operative site in any of a variety of medical procedures employed to treat any number of medical conditions in human and/or animal patients.
2. Description of the Related Art
In many medical procedures, endovascular devices are delivered during diagnostic and surgical procedures, and it is useful and/or necessary to deliver these devices on or over a medical guidewire.
Minimally invasive interventional medical diagnosis procedures in general, and minimally invasive endovascular therapy in particular, are medical events where devices are delivered over a guidewire during the procedure, and each has enjoyed unprecedented expansion to treat patients because of the numerous medical benefits associated with not having to enter the body through more invasive surgical techniques. These benefits include, but are not limited to, less trauma and/or scarring for patients, less time to heal, less risk of infection and decreased length of hospital stays, to name but a few.
More particularly, minimally invasive endovascular therapy is often used to treat diseased vessels, e.g., arteries and veins. With such therapy, small instruments are inserted into the vessels through a puncture or access opening made in one of the vessels at an entry site and are advanced through the circulatory system to an operative site where the vessel has become diseased. There, the instruments are used to diagnose and/or repair the diseased or operative site. Typically, the goal of such therapy is to identify and and treat by dilation full or partial blockages of the diseased vessel. Such blockages may have developed over time or may have developed quickly, as for example, in response to an injury. One common source of such blockage is thromboemboli which has formed in the vessel. Thrombus is an aggregation of platelets, fibrin, clotting factors and cellular components of blood that spontaneously form and attach on the interior wall of a vein or artery. Thromboemboli are emboli of thrombus which operate to partially or completely occlude the interior or lumen of the blood or other vessel.
Techniques to open and/or maintain the dilation of the partially or completely occluded lumen of blood or other vessels include balloon angioplasty and stenting. Balloon angioplasty is the delivering of a balloon over a guidewire and positioning it in an obstruction or partially occluded section of the vessel, inflating the balloon to compress the build up. Stenting is the temporary or permanent inserting, again over a guidewire, of a tube-like support within the vessels to keep the vessel open.
Minimally invasive endovascular diagnosis and therapy has the significant advantages of being less invasive than traditional surgical techniques and causing less trauma to the patient. However, these procedures are also inherently more complicated: they may inadvertently puncture the vessel wall or dislodge and free particles or objects during the procedures as discussed above. Particularly, this complication results from the small clearances between instruments and the interior of the vessels of the body, and reaching the operative site with the tools is very difficult (due to the considerable branching of the circulatory system that may occur between the entry site into the blood vessel and the operative site). Endovascular diagnosis and therapy is further complicated by the fact that the entry site is often far from the operative site, as for example, where the entry site is in the thigh at the femoral artery and the operative site is located in the neck at the carotid artery. Even when the surgeon's instruments have been properly advanced to the operative site, manipulating the tools to perform their respective functions at the operative site is often difficult for the surgeon due to many factors including guidewire movement, the close quarters at the operative site and the distance between the entry site and the operative site.
One method and apparatus commonly used by surgeons to ensure the tools reach the operative site is to first thread a simple guidewire to or beyond the operative site. Thereafter, various tools are threaded over the guidewire by the surgeon to reach the operative site. It is an important aspect of such guidewires that they must be easy to manipulate within the vessels, including, in certain cases, through lesions or areas of blockage in the vessel by the surgeon. In addition to exhibiting sufficient resiliency so as to be pushable in the vessel, the guidewire must exhibit sufficient flexibility and maneuverability to enable the surgeon to traverse the many twists and turns of the circulatory (or other) system to reach the operative site.
Two major aspects which influence the ability of a surgeon to manipulate the guidewire through the circulatory or other system are the guidewire's advancement and “torquability”. As defined herein, “torquability” is a qualitative measure of the surgeon's ability to rotate the proximal region of the guidewire that extends outside of the patient's body during the advancement of the guidewire to the operative site and translate that rotation to the distal end of the guidewire. It is this rotation at the proximal region of the guidewire, when mechanically transmitted to the distal end of the guidewire, which advances the distal end through the patient's blood or other vessels to the operative site. A lack of correlation between rotation at the proximal region of the guidewire and rotation at the distal end of the guidewire is referred to as reduced torquability and is undesirable. A high degree of correlation is referred to as a high degree of torquability and is desirable. As may be appreciated, it is most desirable for the guidewire to have an exact correlation or high torquability between the rotation applied proximally at the proximal region of the guidewire and the rotation developed distally in the guidewire, so that the surgeon can carefully control, advance, and direct the medical guidewire. With known devices, there is considerable difference between the amount of rotation applied at the proximal region of the guidewire and the amount of rotation developed at the distal end of the guidewire, making it very difficult for surgeons to maneuver the distal end of the guidewire.
Even where the guidewire exhibits the desired torquability characteristics, and the tools have been properly threaded to the operative site and have been properly manipulated to perform their respective functions at the operative site, there remains the problem noted above, namely, that the process of dilating the occlusion and/or inserting the stent may dislodge or free small particles or objects, also known, among other things, as clots, fragments, plaque, emboli, thromboemboli, etc. More particularly, with respect to endovascular therapy, the term “embolic event” has come to be used to describe complications where thrombus or plaque is shed inadvertently from a lesion to migrate to smaller vessels beyond the operative site to create a full or partial occlusion of the lumen of the vessel or vessels. This is most undesirable and can lead to many complications. These complications are dependent upon the site in the body where such emboli become lodged, downstream of the operative site. They include stroke, myocardial infarction, kidney failure, limb loss or even death. With increasing emphasis, surgeons state the need to reduce the likelihood of complications such that assurance against embolic events will become the typical result of endovascular therapy.
During the previously described procedures, it is necessary to remove tools, devices and catheters from a patient via a guidewire while the guidewire itself remains in the patient. Typically during a procedure, a torquer is placed on and removed from a guidewire each time a new device is utilized. This necessitates the complete removal of the torquer from the guidewire by sliding the torquer to the proximal end of the guidewire. The guidewire being of considerable length, relates to several awkward motions which again can cause damage to the intima of the vessel. The torquer is also advanced several times along the guidewire with the use of each new tool. With most torquers, this requires a two-handed action to loosen, slide and then retighten the torquer before the next step in the procedure can be made, this is time consuming and costly to both the physician and patient.
Devices are seen in the art that assist in the manipulation of the guidewire external to the surgical opening, such that the internally displaced distal end of the guidewire may be maneuvered through the vessel as a result of movement from the guidewire's proximal end.
U.S. Pat. No. 6,030,349 to Wilson et al. teaches a medical guidewire torquer comprising a single cylindrical body having a groove displaced therein for receiving the wire, wherein an amount of pressure may be applied to the medical guidewire so movement and immobilization of the torquer along the proximal end may be performed.
U.S. Pat. No. 5,325,868 to Kimmelstiel shows a self-gripping medical wire torquer which includes a single sleeve body having a clamping device and a release mechanism for temporarily releasing the clamp means to slide and reposition the torquer along the wire.
Other devices for manipulating a medical guidewire are known in the art, but these and the above devices suffer generally, not only because of the above reasons for lack of torquability, but because of cost considerations and their inherent complexity. Because of concerns for sterility, and the need for ease of use, a surgeon will typically dispose of torquer devices regularly during different stages of the advancement of the guidewire, even for the same patient. Surgeons have found that it is more expedient to have many disposable torquer devices available than to repeatedly reposition and keep track of a single torquer. For this reason, simplicity of design and the ease of use by one-hand manipulation is of utmost importance.
There is need then in the art for a torquer device to maximize torquability, which is simple in design, easy to mount on, slide upon, and remove from the medical guidewire, using a single-hand clamping technique.